Matching Items (2)

Filtering by

Clear all filters

134581-Thumbnail Image.png

Does an extended washout period of six weeks following the end of chronic stress continue the benefits on spatial learning and memory?

Description

Chronic stress often leads to cognitive deficits, especially within the spatial memory domain mediated by the hippocampus. When chronic stress ends and a no-stress period ensues (i.e., washout, WO), spatial ability improves, which can be better than non-stressed controls (CON).

Chronic stress often leads to cognitive deficits, especially within the spatial memory domain mediated by the hippocampus. When chronic stress ends and a no-stress period ensues (i.e., washout, WO), spatial ability improves, which can be better than non-stressed controls (CON). The WO period is often the same duration as the chronic stress paradigm. Given the potential benefit of a post-stress WO period on cognition, it is important to investigate whether this potential benefit of a post-stress WO period has long-lasting effects. In this project, chronic restraint (6hr/d/21d) in Sprague-Dawley rats was used, as it is the minimum duration necessary to observe spatial memory deficits. Two durations of post-stress WO were used following the end of chronic restraint, 3 weeks (STR-WO3) and 6 weeks (STR-WO6). Immediately after chronic stress (STR-IMM) or the WO periods, rats were tested on various cognitive tests. We corroborated past studies that chronic stress impaired spatial memory (STR-IMM vs CON). Interestingly, STR-WO3 and STR-WO6 failed to demonstrate improved spatial memory on a radial arm water maze task, performing similarly as STR-IMM. Performance outcomes were unlikely from differences in anxiety or motivation because rats from all conditions performed similarly on an open field task and on a simple object recognition paradigm, respectively. However, performance on object placement was unusual in that very few rats explored, suggesting some degree of anxiety or fear in all groups. One possible interpretation of the unusual results of the 3 week washout group may be attributed to the different spatial memory tasks used across studies or external factors from the study. Further exploration of these other factors led to the conclusion that they did not play a role and the STR-WO3 RAWM data were anomalous to other studies. This suggests that a washout period following chronic stress may not be fully understood.

Contributors

Agent

Created

Date Created
2017-05

136429-Thumbnail Image.png

The effects of urbanization and human disturbance on problem solving in juvenile house finches (Haemorhous mexicanus)

Description

Urbanization exposes wildlife to many unfamiliar environmental conditions, including the presence of novel structures and food sources. Adapting to or thriving within such anthropogenic modifications may involve cognitive skills, whereby animals come to solve novel problems while navigating, foraging, etc.

Urbanization exposes wildlife to many unfamiliar environmental conditions, including the presence of novel structures and food sources. Adapting to or thriving within such anthropogenic modifications may involve cognitive skills, whereby animals come to solve novel problems while navigating, foraging, etc. The increased presence of humans in urban areas is an additional environmental challenge that may potentially impact cognitive performance in wildlife. To date, there has been little experimental investigation into how human disturbance affects problem solving in animals from urban and rural areas. Urban animals may show superior cognitive performance in the face of human disturbance, due to familiarity with benign human presence, or rural animals may show greater cognitive performance in response to the heightened stress of unfamiliar human presence. Here, I studied the relationship between human disturbance, urbanization, and the ability to solve a novel foraging problem in wild-caught juvenile house finches (Haemorhous mexicanus). This songbird is a successful urban dweller and native to the deserts of the southwestern United States. In captivity, finches captured from both urban and rural populations were presented with a novel foraging task (sliding a lid covering their typical food dish) and then exposed to regular periods of high or low human disturbance over several weeks before they were again presented with the task. I found that rural birds exposed to frequent human disturbance showed reduced task performance compared to human-disturbed urban finches. This result is consistent with the hypothesis that acclimation to human presence protects urban birds from reduced cognition, unlike rural birds. Some behaviors related to solving the problem (e.g. pecking at and eying the dish) also differed between urban and rural finches, possibly indicating that urban birds were less neophobic and more exploratory than rural ones. However, these results were unclear. Overall, these findings suggest that urbanization and acclimation to human presence can strongly predict avian response to novelty and cognitive challenges.

Contributors

Agent

Created

Date Created
2015-05